From the opening with a child slashing someone and a bloody knife dropping to the floor, we're plunged into an ever-deepening pool of repressed terrors. David Hemmings is a pianist sucked into an undertow of escalating homicide after he witnesses the murder of psychic Macha Meril. One of Argento's most justly famous gialli, where something as simple as a lizard writhing on the floor could represent a child's wounded psyche, bound someday to erupt in spectacular fits of murder. The dark and distinctive, keyboard-rich soundtrack - the first by prog rockers Goblin - was a major hit in Italy. With Daria Nicolodi.